GitLab

Move the Wi-Fi configurations to UserSelectableOsType. Change the
ModelTypeController to respect the global "OS sync enabled" pref.
Refactor the printers ModelTypeController to share code.

Note: This means Wi-Fi config sync cannot ship before Split Settings
Sync.  However, it's much simpler than trying to support Wi-Fi config
being *both* a UserSelectableType and a UserSelectableOsType.
I've discussed this with the engineer working on Wi-Fi sync and we're
both OK with this plan.

Bug: 1013466
Test: existing components_unittests and unit_tests
Test: Run --enable-features=SplitSettingsSync,SyncWifiConfigurations
  and verify "Wi-Fi configurations" appears in Chrome OS settings.
  Verify turning it off and closing settings results in
  chrome://sync-internals showing that the Wi-Fi type is not syncing.

Change-Id: I878fecaf449248ae8747e37aa2e0e897130e63ad
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1947396Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Marc Treib <treib@chromium.org>
Commit-Queue: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#721541}